What's new
Van's Air Force

Don't miss anything! Register now for full access to the definitive RV support community.

cracked engine mount

hangerratt

I'm New Here
Is there anyone who repairs cracked engine mounts for a RV3. Just landed and the right wheel turned out 30 degrees. Good thing I was landing on my grass strip and not on pavement.
 
Is there anyone who repairs cracked engine mounts for a RV3. Just landed and the right wheel turned out 30 degrees. Good thing I was landing on my grass strip and not on pavement.

Give Russ McCutcheon a call. He lives/works just north of Portland, OR. He has a business making engine mounts for Vans. "Russ McCutcheon" is also his name on VAF, so you might send him a PM.

Great guy! - - I visited his shop when visiting the area.
 
Thanks Bill.

Hi Eric and welcome to VAF! I don't build the -3 mount but will be happy to help if I can, e-mail me some photos of the damage and we will talk about it.
 
RV-3 Engine Mount Crack

...Just landed and the right wheel turned out 30 degrees...

Which engine do you have on your 3 and when you get a chance could you post a picture of the crack? I have an O-290 and mine cracked on the bottom cross piece at about the 150 hr point...

Doug
RV-3A Sold; RV-9A Mazda 13B FWF (still waiting to be finished)
 
3 Pics

I have a friend with a 3, 0-320 and would like to also see the pictures you have of the crack.

Thanks hangerratt
 
I have seen cracks on both sides of a RV-6 engine mount to main gear leg area. The gear attach point area I think needs to be inspected closely on all models. I think Vans has reinforced the newer mounts, don't have the details, in the areas being discussed.
 
I have seen cracks on both sides of a RV-6 engine mount to main gear leg area. The gear attach point area I think needs to be inspected closely on all models. I think Vans has reinforced the newer mounts, don't have the details, in the areas being discussed.

The newer mounts have significant reinforcement in the lower mount/gear leg tube intersection.
 
how do you attach a picture to a post?

I think it would be easier just to come take off your mount.

Photos are not uploaded to this site. They are referenced from their web location with a link. The photos have to be publicly available and using a compatible website. I use Picasa - a Google service -free - and it works pretty well. It uses the same gmail address to access.

So - do you upload pictures to share today? If so, what service do you use?

Edit - you could just send it to me and I will post if that helps.
 
Pick of Eric's mount.

IMAG1305.jpg

I'll have it in the shop next week.
 
Engine Mount Crack

Nice picture. My cross piece cracked as well, but on the tubing just off the weld, and didn't effect the socket. I cut it out completely, smoothed it on both sockets, and ordered the next size thicker tubing than stock and had a buddy TIG it up. Hopefully the thicker material will resist future cracking; but I know there are quite a few guys who have also added gussets there in an attempt to better spread the landing shock loads to the sockets as well.

Hope you get it back in the air soon...down time for MX is a bummer! :)

Doug
 
Cracked mount.

I bought m RV3 with a (badly)cracked mount in a similar location. It had been repaired at least once before and upon inspection it was determined that the previous repairs were not up to snuff, they did not remove the mount and thus, did not get the weld right.
I purchased a new mount and gear legs from Vans, and it was a H-U-G-E project to replace it. Lots of work, adjustment, and such on the firewall, the bolts didn't match up right, and the gear is slightly different angle which meant that I had to adjust the leg fairings and wheel pants. Also, after getting the engine hung, the spinner was low and the cowl had to be tweeked as well.
It is done, and flying, it has the new beefier mount mentioned in other posts, but it was a lot of work. If you can get a skilled welder to fix the one you have and add the gussets, maybe thicker tube as suggested, you will be way better off.
Best of luck
Dave
 
Are engine mount cracks always that obvious? I'll be disassembling the front end of Tony Boy at some point and giving the mount a thorough inspection. It looks sound, but is there a more thorough inspection method to do than just blasting the paint off and looking it over?
 
Are engine mount cracks always that obvious? I'll be disassembling the front end of Tony Boy at some point and giving the mount a thorough inspection. It looks sound, but is there a more thorough inspection method to do than just blasting the paint off and looking it over?

Katie: No one can guarantee that it will be really obvious right away; but it will show itself in all its' glory eventually! :) I had my mount powder coated, and my crack initially looked like a very narrow black line, and it wouldn't wipe off so I got my knife out and scrapped off the white paint and found a tiny crack that went 3/4 of the way around the tube. I think it's best to take the cowling off every 20-25 hrs and give everything a good once over, looking for any issues likes this...

Fly safe,

Doug
 
That crack looks like it runs right along the weld root. Are these mounts factory welded or by the builder?

Any indication of where the crack initiated? In the heat affected zone? At an inclusion or other flaw in the weld?
 
Are engine mount cracks always that obvious? I'll be disassembling the front end of Tony Boy at some point and giving the mount a thorough inspection. It looks sound, but is there a more thorough inspection method to do than just blasting the paint off and looking it over?

Yes, since you will have it off, the best is a magna flux, but dye penetrant can be used too. Automotive machine shops would use magna flux. The technique is still used, but availability might be more of an issue.

Edit: You might call Hasting Race engines (Shelbyville) - they would know where to get it done.
 
Last edited:
RV3 engine mount cracking

The RV3 engine mount will often crack like that when the two center-mount points are not present (there are six through-the-firewall mount bolts on the RV3 engine mount - the two center points were introduced around 1985). The problem is well known: the upper gear leg socket will rock back and forth on hard landings or uneven terrain and will eventually crack. The same six-point attach was made standard on the RV4 design from early on.

When you get the repairs done, just have the two additional mount tubes welded on at the same time. It requires some additional structure on the fwd fuselage floor, but you can do that at your leisure - contact Van's for details. All your engine mount cracking problems will go away with that modification - I've got over 3000 landings on an RV3 modified like that, with plenty of thunder-in bounces, and no cracks or other problems with the mount at all.

- Steven
(850 RV3 hours - another one yesterday!)
 
Back
Top